1. Field of the Invention
The present invention relates to a sprayable aerosol composition which is a liquid in the aerosol container and forms a gel upon application to the skin.
2. Prior Art
The preparation of aqueous gels employing as gelling agents polyoxyalkylene block copolymers is well known to those skilled in the art and is taught in several patents including U.S. Pat. No. 3,740,421.
The use of polyoxybutylene-polyoxyethylene block copolymers in the preparation of aqueous gels is known to those skilled in the art. More specifically, U.S. Pat. No. 4,343,785 discloses a gel dentifrice containing such block copolymers.
U.S. Pat. No. 3,751,562, issued Aug. 7, 1973, to Nichols, discloses an aerosol gel formulation employing an oxyethylated fatty alcohol, mineral oil, iodine and water.
U.S. Pat. No. 4,293,542, issued Oct. 6, 1981, to Lang et al, discloses aerosol formulations which can be an aqueous gel containing oxyethylated fatty alcohols and a gel-forming agent and, as an essential component, a pyridine derivative.
It is known in the art to apply such compositions by the use of aerosol-type containers. However, filling an aerosol container with a gel presents problems.
British Pat. No. 1,096,357 discloses an aerosol gel comprising a partial fatty acid soap of a polyvalent metal hydroxide, a nonpolar oil along with propellants.
The treatment of burns with medicated liquid such as silver ion solutions is well known in the art as evidenced by Moyer et al, Arch, Surg. 90, June, 1965. Briefly, the known treatments of burns comprise applying a solution of medication such as a silver nitrate solution to a burn wound. Because this treatment involves liquid solutions, it is known as a wet dressing method. The conventional wet dressing method suffers from many disadvantages. Some of these include (1) exacerbation of the hypermetabolic state by increasing caloric deficit and heat loss, (2) loss of plasma water, serum protein, and serum electrolytes, (3) maceration of burn wound surfaces, (4) increase of fluid loss by vaporization, (5) extensive nursing care, (6) economic loss due to discoloration of bedding, equipment, floors and walls. With so many disadvantages, it is not surprising that the art has searched for an alternate method of treating burns.
In U.S. Pat. No. 3,476,853, a sprayable composition for use as a dressing including a film-forming material, an opacifying material, at least one medicament, a solvent and a gaseous propellant is disclosed. The fluid dressing or bandage is applied by spraying the fluid dressing from a closed pressure-resistant container by the expansion of a normally gaseous propellant in liquid state. The patent discloses a means for applying a protective opaque film which is immediately dry to the touch when applied from a distance of 4 to 6 inches. This provides a simulated bandage.
U.S. Pat. No. 3,639,575 discloses compositions prepared from aqueous gels of polyoxyethylene-polyoxypropylene block copolymers as a matrix for silver ions for burn treatment. There is no disclosure of spraying from an aerosol container.
U.S. Pat. No. 4,376,764 discloses silver ion gel compositions containing a polyoxybutylene-polyoxyethylene block copolymer. These gel compositions may be used to treat burn wounds and superficial ulcers.
British Pat. No. 1,444,334 discloses an aerosol gel composition which may be employed as a shaving cream and which contains as a gelling agent a polyoxypropylene-polyoxyethylene block copolymer. An essential component of the composition is a water-soluble soap. This patent is concerned with the problem of expelling a gel from an aerosol container and particularly avoiding cavitation around the dip tube. Accordingly, the compressed gas or liquified gaseous propellant is required to be substantially insoluble in the gel so that it can act in the manner of a piston to force the gel from the container without cavitation.
Co-pending U.S. patent applications Ser. Nos. 513,439, 525,147, and 524,985 disclose aerosol gel compositions which are liquid in the aerosol can and form a gel upon application to the skin.